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Functional Imaging of Auditory Cortex in Adult Cats using High-field fMRI
Published on: February 19, 2014
Age-Related Changes in Temporal Processing of Rapidly-Presented Sound Sequences in the Macaque Auditory Cortex
Chi-Wing Ng1, Gregg H Recanzone2,3
1Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, USA.
Cerebral Cortex (New York, N.Y. : 1991)
|October 18, 2017
Summary
Aging impairs the auditory cortex's ability to process rapid sounds. Older monkeys showed altered neural activity and less precise temporal coding, potentially explaining age-related speech comprehension difficulties.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Aging Research
Background:
- The mammalian auditory cortex is vital for processing temporal sound features, essential for speech comprehension.
- Auditory processing declines with normal aging, but its impact on temporal coding in the auditory cortex is not fully understood.
- Nonhuman primate models offer insights into age-related changes in the auditory nervous system.
Purpose of the Study:
- To investigate the effects of aging on temporal processing in the auditory cortex of nonhuman primates.
- To compare neural activity and coding strategies in young versus old monkeys during auditory tasks.
Main Methods:
- Electrophysiological recordings from the auditory cortex (core and lateral belt areas) in awake young and old monkeys.
- Presentation of tone-pip and noise-burst sound sequences to assess neural responses.
- Analysis of spontaneous and stimulus-driven neural activity, discharge patterns, phase-locking, and population coding strategies.
Main Results:
- Older monkeys exhibited elevated spontaneous and stimulus-driven neural activity.
- Neurons in older monkeys showed less precise phase-locking to stimulus envelopes.
- Functional specialization in temporal coding between auditory cortex areas was diminished in older monkeys.
- Population activity shifted from sparse, selective coding in young monkeys to homogenous, distributed coding in old monkeys.
Conclusions:
- Aging degrades temporal fidelity in the auditory cortex, characterized by less precise neural timing and altered coding strategies.
- These neural changes, including broadly-tuned responses in aged auditory cortex, may underlie difficulties in processing dynamic sounds and speech in older individuals.
- The findings highlight the neural mechanisms contributing to age-related deficits in auditory perception and speech comprehension.
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